Spark plug



June 19, 1934. E, owos LsK 1,963,714

SPARK PLUG Filed Jan. 25, 1932 INVENTOR Edward 5 NowoJ//Jki PatentedJune 19, 1934 PATENT- OFFICE SPARK PLUG Edward B. NowosielskLBloomfleld,N. J., assignor. by mesne assignments, to Eclipse Aviation Corporation,East Orange, N. J., a corporation of New Jersey 7 Application January25, 1932, Serial No. 588,759

. I 15. Claims.

This invention relates to spark plugs and particularly to spark plugs ofthe type capable of producing proper ignition in internal combustionengines of the relatively high compression class.

An object of the invention is to provide a new and improved spark plugof relatively great durability by reason of the incorporation therein ofa novel combination and interrelation of parts producing a unit which iscapable of withstanding the highest temperatures and compressionsencountered under the most trying operating conditions.

Another object of the invention is to provide in a spark plug of thetype in which one of the electrodes is in the form of a centrallydisposed pin or spindle, novel means for insuring a gastight jointaround said spindle.

Another object of the invention is to provide in a spark plug having acentrally disposed electrode as above described, hovel means engageablewith said electrode for transferring to the outer shell the stresses setup in the plug as an incident to its assembly and installation, andparticularly as an incident to the establishment of the gastight jointabove referred to.

These and other objects of the invention will be apparent to thoseskilled in the art from the following description, taken in connectionwith the accompanying drawing wherein are illus- 50 trated twoembodiments of the invention. It is to be expressly understood, however,that the drawing is for the purpose of illustration only and is notdesigned as a definition of the limits of the invention, reference beinghad for this purpose to the appended claims.

Referring to the drawing,

'Figs. 1 and 2 are central longitudinal sections through two embodimentsof the invention. Fig. 3 shows in perspective an element of Fig. 2.

Referring first't-o the embodiment disclosed in Fig. 1, the invention istherein shown incorporated in a unitary structure disposed about acenter electrode 5 which, as shown, is upset, after assembly, to form ahead 6, the under surface of which is tapered to provide a firm seatupon the counter-bored upper surface of metallic cap '7,

the latter being circumferentially grooved, as indicated at 8, forreception of a suitable terminal clip or equivalent conductor (notshown) by which ignition current may be led to the spark plug from theusual current supplying unit.

The center electrode- 5 -is preferably formed with a slight taper and atan appropriate distance above its lower end is provided with a shoulderor ledge 10 forming a support for a multi-layered sleeve 11 ofinsulating material extending along the surface of the electrode 5 to apoint just above the tapered central opening 12 in the lower end of thecap '7. This shoulder or ledge 10, in addition to its function ofsupporting the insulating sleeve 11, also coacts with the elements yetto be described to provide a novel construction for transferring to thecylinder head, into which the shell 15 of the plug is threaded, thestresses resulting from a tightening of the gas-seal means now to bedescribed.

The novel means for insuring a gas-tight seal around the centerelectrode 5 comprises the insertion of a metallic sleeve 17 having anexternally tapered surface adapted to register with a correspondinglyinternally tapered bore provided in the surrounding tightening nut 18,the latter having its upper portion 19 cut to form regular polygonalsides facilitating the reception of a wrench by which the assembly maybe tightened, and the upper surface of the nut serving as a support forthe usual assembly of insulating washers 20 varying in diameter fromthat of the upper surface of the nut 18 to that of the lower surface ofthe cap 7 in the usual manner, as indicated. The central portion of theouter surface of the nut 18 is threaded for engagement with thecorresponding threads 22 upon the interior bore of the upper portion ofthe shell 15, the intermediate portion 23 thereof being flanged toconstitute a limiting means for engagement with the outer surface of thecylinder head into which the plug is inserted.

The lower surface of the sleeve 17 and the nut 18 are correspondinglybeveled, as indicated at 24 and 25, respectively, to register with asimilarly inclined upper surface provided on a cooperating sealingmember 27 of relatively soft metal adapted to become plastic underpressure and form a gas-tight seal against the sloping ledge or shelfand within an annular ledge 29 on the interior surface of the shell 15.From this ledge 29 the sealing member 27 extends downward to engage asecond group of insulating washers 35 of a diameter corresponding tothat of the lower section of the bore of the shell 15, the said group ofwashers being supported upon the annular floor or base 36 of the shell15. On examination of Fig. 1 it will be seen that at a point a slightdistance below the shoulder 10 on the center electrode 5, the washers 35extend inwardly beneath the said shoulder and provide a seat for ametallic supporting ring 37 on which the said shoulder 10 is adapted tobe received as the center electrode is inserted into the shell andwashers 35 in the process of amembly.

From the foregoing it is evident that when the parts have been assembledin the indicated man ner, the plug is made gas-tight by turning up onthe nut 18, such turning actionoperating upon the sleeve 1'7, throughthe cooperating wedging surface thereon, to press the said sleeve firmlyaround the insulating sleeve 11, thus pressing the latter firmly aroundthe electrode 5 and preventing the passage of any gas therebetween. Atthe same time, the stresses set up in the parts through this tighteningaction is transferred to the associated engine cylinder by being passedon through the member 2'? and washers 35 to the'shell 15. This transferof stress to the engine cylinder protects and relieves the plug itself,and every part thereof, of such strain. This is a decided improvementover previous constructions wherein such stresses are transferred to thecenter electrode and thus operate to weaken either the electrode or thepart (usually the upper cap) from which the electrode is suspended. Withthe present construction, it will be further noted, the electrode is notsuspended from its upper end, as in previous construction, but is on thecontrary supported on the metal ring 37, near its lower end, the ringbeing in turn supported on the base 36 of the shell through theintermediary of the washers 35.

The embodiments shown in Fig. 2 is similar in principle to that of Fig.1, but differs therefrom in the shape of the wedging sleeve 57 and inthe provision of an additional wedging member 58 intermediate thetightening nut 19 and the reaction absorbing abutment constituted by theinclined ledge 60 of the shell 15. A further novel feature of thisembodiment is the provision of a pair of washers 63 and 64, the formerof relatively soft metal adapted to be pressed firmly upon the ledge 60to form a gas-tight seal therewith, and the latter being of metalhardened and serrated as better shown in Fig. 3 on its outer peripheryto bit into the inner bore of the shell 15 and thus maintain the discs35 firmly packed.

With this embodiment of the invention it is apparent that tightening ofthe nut 19 acts to produce a wedging effect upon both the upper andlower tapered surfaces of the sleeve 57, thus insuring a moreeffectively directed lateral pressure on the sleeve 57 and hence anextremely efficient seal around the electrode as well as along thesurface of the shells. In this embodiment also, there is provided alimiting means for the tightening action in the form of centrallydisposed rim 62 which, by virtue of engaging the nut 19 or the wedgingmember 58, will act as a stop on the wedging action.

While both embodiments of the invention herein disclosed possessconsiderable practical merit, it is to be expected that changes may bemade in the shape and relative arrangements of the parts within thenovel principles herein disclosed; and accordingly such variations areto be considered within the scope of the present invention if fairlyincluded within the language of the appended claims.

What is claimed 1. In a spark plug of the type having an external shelladapted to be inserted in the cylinder wall of an internal combustionengine, the combination with said shell of a conducting spindlecentrally mounted therewithin, said spindle having a surrounding sleeveof insulating material and a shoulder extending radially therefromintermediate its ends, said shoulder constituting the means by whichsaid spindle is supported O said shell, a pair of wedging memberssurrounding said insulating sleeve and means engageable with said shellfor causing one of said wedging members to apply lateral pressure onsaid insulating sleeve to form a gas-tight seal around said spindle.

2. In a spark plug of the type having an external shell adapted to beinserted in the cylinder wall of an internal combustion engine, thecombination with said shell of a conductingspindle centrally mountedtherewithin, a sealing member surrounding said spindle, a second sealingmember engageable with said shell, a wedging member engageable with bothsaid sealing members, and means interposed between said wedging memberand said shell for applying pressure through said wedging member to bothsaid sealing members.

3. In a spark plug of the type having a center electrode and an outershell attachable to an engine cylinder, a base integral with said shelland centrally apertured to receive the lower end of the centerelectrode, a plurality of insulating members encircling and supportingsaid electrode, said members being in turn supported upon said base, anut threaded to said shell, and a hardened metallic locking membermovable into clamping relation to said insulating members in response totightening of said nut.

4. In a spark plug of the type having an outer shell attachable to anengine cylinder, a base integral with said shell and centrally aperturedto receive the lower end of the center electrode, a plurality ofinsulating members surrounding and supporting said electrode, saidmembers being in turn supported upon said base, a nut threaded to saidshell, and a serrated metallic disc movable into clamping relation tosaid insulating members in response to tightening of said nut.

5. In a spark plug of the type having an external shell adapted to beinserted in the cylinder wall of an internal combustion engine, thecombination with said shell of a conducting spindle centrally mountedtherewithin, an insulating sleeve wrapped about said spindle, a metallicsleeve fitting closely about said insulating sleeve, said metallicsleeve having a tapered outer surface and a beveled end, and commonmeans for sealing both said shell and spindle comprising an annulargland seated in the shell and having one end beveled to register withthe beveled end of said metallic sleeve, and a sealing nut threadedlyengaging said shell, said nut also having a beveled end registering withthe beveled end of said annular gland, and an internal taper registeringwith the tapered outer surface of said metallic sleeve, in such a manneras to cause the latter to be pressed firmly against both said insulatingsleeve and said annular gland when the nut is screwed into the shell.

6. In a spark plug of the type having an external shell adapted to beinserted in the cylinder wall of an internal combustion engine, thecombination with said shell of an electrode centrally mountedtherewithin, an insulating member encircling said electrode, a metallicsleeve encircling said insulating member, said metallic seeve having abeveled end, a sealing member having one end beveled to register withthe beveled end of said metallic sleeve, and a nut threadedly engagingsaid shell, said nut having a beveled i end registering with the beveledend of said sealing member and also registering with said metallicsleeve to cause the latter to be pressed firmly 150.

against both said insulating sleeve and said sealing member when the nutis screwed into the shell.

7. In a spark plug of the type having an external shell adapted to beinserted in the cylinder wall of an internal combustion engine, thecombination with said shell of a conducting spindle centrally mountedtherewithin, an insulating sleeve wrapped about said spindle, a metallicsleeve fitting closely about said insulating sleeve, said metallicsleeve having a tapered outer surface and a beveled end, a sealingmember seated in the she I and having one end beveled,,to register withthe beveled end of said metallic sleeve, and a nut threadedly engagingsaid shell, said nut also having a beveled end registering with thebeveled end of said sealing member and an internal taper registeringwith the tapered outer surface of said metallic sleeve in such a manneras to cause the latter to be pressed firmly against both said insulatingsleeve and said sealing member when the nut is screwed into the shell.

8. In a spark plug of the type having an outer shell attachable to anengine cylinder and an electrode extending centrally through said shell,a plurality of insulating discs encircling and supporting saidelectrode, said discs being in turn supported by said shell, a nutthreadedly engaging said shell, and a hardened metallic locking membermovable into clamping relation to said discs in response to tighteningof said nut.

9. In a spark plug of the type having an outer shell attachable to anengine cylinder and an eiectrode extending centrally through said shell,a plurality of insulating discs encircling and supporting saidelectrode, said discs being in turn supported by said shell, a nutthreadedly engaging said shell, and a serrated metallic disc movableinto clamping relation to said insulating discs in response totightening of said nut.

10. In a spark plug of the type having an outer shell attachable to anengine cylinder and an electrode extending centrally through-saidshell,a plurality of insulating members encircling and supporting saidelectrode, said members being in turn supported by said shell, a nutthreadedly engaging said shell, and a hardened metallic looking membermovable into clamping relation to said members in response to tighteningof said nut.

11. In a spark plug of the type having an outer shell attachable to anengine cylinder and an electrode extending centrally through said shell,a plurality of insulating members encircling and supporting saidelectrode, said members being in turn supported by said shell, a nutthreadedly engaging said shell, and a serrated metallic member movableinto clamping relation to said members in response to tightening of saidnut.

12. In a spark plug of the type having an external shell adapted-to beinserted in the cylinder wall of an internal combustion engine, the

' combination with said shell of a conducting spindle centrally mountedtherewithin, an insulating sleeve encircling said spindle, a metallicsleeve fitting closely about said insulating sleeve, said metallicsleeve having a tapered outer surface,

an annular gland seated in the shell and having its upper endregistering with the lower end of said metallic sleeve, and apressure-applying nut threadedly engaging said shell, said nut havingregistry with the upper end of said annular gland and a tapered innersurface registering with the tapered outer surface of said metallicsleeve in such a manner as to cause the latter to be pressed firmlyagainst both said insulating sleeve and said annular gland when the nutis screwed into the shell.

13. In a spark plug having a cylinder engaging shell and a centerelectrode extending therewith, an insulating sleeve encircling saidcenter electrode. a metallic sleeve encircling said insulating sleeve,said metallic sleeve having a tapered outer surface, an annular shelf onthe inner surface of said shell, an annular gland having its lowersurface registering with said shelf and its upper surface registeringwith said metallic sleeve, and a pressure-applying nut threadedlyengaging said shell, said nut having a tapered inner surface registeringwith the tapered outer surface of said metallic sleeve to cause thelatter to be pressed firmly against both said insulating sleeve and saidannular gland when the nut is screwed into the shell.

14. In a spark plug having a cylinder engaging shell and a centerelectrode, an insulating sleeve encircling said center electrode, ametallic sleeve encircling an intermediate portion of said insulatingsleeve, said metallic sleeve having a tapered outer surface, a pluralityof insulating washers encircling said insulating sleeve within saidshell, annular means having a portion registering with said metallicmeans, a portion in engagement with said shell, and a portion inengagement with one ofsaid washers, and a pressure-applying nutthreadedly engaging said shell and having a tapered inner surfaceregistering with the tapered outer surface of said metallic sleeve tocause the latter to be pressed firmly against said insulating sleeve, toeffect a gas sealing engagement between said second named portion of theannular means and the shell, and to cause a compression of said washersthrough said tht'rd named portion of the annular means when the nut isscrewed into the shell.

15. In a spark plug having a cylinder engaging shell and a centerelectrode, an insulating sleeve encircling said center electrode, ametallic sleeve encircling said insulating sleeve, said metallic sleevehaving a tapered outer surface, annular means having a portionregistering with said metallic sleeve and a portion in engagement withsaid shell, and a pressure-applying nut threadedly engaging said shelland having a tapered inner surface registering with the tapered outersurface of said metallic sleeve to cause the latter to be pressed firmlyagainst said insulating sleeve and to effect a gas sealing engagementbetween said second named portion of the annular means and the shellwhen the nut is screwed into the latter.

EDWARD B. NOWOSIEISKI.

